| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 35°F | 60°F | 46°F | 1.8" |
| February | 39°F | 65°F | 50°F | 1.0" |
| March | 47°F | 72°F | 58°F | 1.7" |
| April | 54°F | 79°F | 65°F | 2.6" |
| May | 62°F | 84°F | 72°F | 4.4" |
| June | 70°F | 92°F | 80°F | 3.5" |
| July | 72°F | 95°F | 83°F | 1.6" |
| August | 72°F | 95°F | 83°F | 1.6" |
| September | 66°F | 89°F | 76°F | 1.4" |
| October | 55°F | 80°F | 66°F | 1.9" |
| November | 46°F | 70°F | 56°F | 1.7" |
| December | 37°F | 60°F | 47°F | 1.4" |
| Index | Stephenville | Texas | National |
| Air quality index | 33 | 52 | 42 |
| Pollution index | 726,578 | 2,009,300 | 2,726,193 |
| Measurement | Total |
| Days measured | 365 |
| Days with good air quality | 329 |
| Days with moderate air quality | 33 |
| Days w/ poor A.Q. for sensitive groups | 3 |
| Days with unhealthy air quality |
| Pollutant | Total |
| Arsenic | 0.001% |
| Benzene | 0.010% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.003% |
| Mercury | 0.000% |
| City | Population | Air Quality Index | National Avg. |
| Dublin, TX | 3,639 | 33 | 34.0% |
| Stephenville, TX | 21,421 | 33 | 34.0% |
| City | Population | Air Quality Index | National Avg. |
| Green Valley, AZ | 21,416 | 47 | 6.0% |
| Gardner, MA | 21,410 | 40 | 20.0% |
| New Hope, MN | 21,432 | 46 | 8.0% |
| Hays, KS | 21,398 | 15 | 70.0% |
| Ferguson, MO | 21,445 | 54 | 8.0% |
| Stephenville, TX | 21,421 | 33 | 34.0% |